Abrasive cutter

ABSTRACT

An asphalt cutter that includes a hollow cylindrical body with a plurality of longitudinally aligned, curved teeth evenly spaced apart along the body&#39;s lower perimeter edge. The teeth are curved in a forward direction of the normal rotation of the body during use with a hardened carbide edge formed thereon. The teeth are slightly wider in cross-section than the side wall of the cylindrical body. During use, a circular gap is formed in the asphalt which enables a center plug formed therein to be easily removed by utility workers. Attached to the top end of the cylindrical body is a longitudinally aligned hollow neck with a top opening. During assembly, the drive shaft on a hydraulic motor attached to the articulating boom is inserted into the neck. A bolt connects the neck and drive shaft together. In the preferred embodiment, an optional elongated guide flag is longitudinally aligned with the cutter. During operation, the operator watches an arrow indicator printed on the side of the guide flag to maintain the drive shaft and cylindrical body in a vertically aligned position over the asphalt during the cutting process.

This is a utility patent application which claims benefit of U.S. Provisional Application No. 60/856,083 filed on Nov. 1, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to rotating abrasive drill bits, and more particularly to abrasive drill bits capable of being used to drill holes in asphalt.

2. Description of the Related Art

Underground utility companies often must cut holes in asphalt roads and parking lots. Heretofore, utility companies have used a diamond bit to drill through the asphalt. Typically, a hole drilling team arrives at the site and creates a series of holes in the road or parking lot that later are used by a team of utility workers to install new utilities or to repair or replace old utilities. In order to cut holes with a diamond bit, a continuous stream of water must be applied to the drill bit to dissipate heat and to reduce friction.

In most instances, the holes are drilled in locations where a continuous water source is not available. In these locations, water must be transported to the drilling site in a large water tank located on a flat bed truck driven to the location. A hose connected to the water tank then delivers the continuous stream of water to the diamond bit.

Because asphalt roads and parking lots are typically six to eight inches thick, a substantial amount of water is normally dispensed which settles upon and eventually floods the areas of the road and the parking lot that surrounds the hole. Also, because this water contains dirt and silt, many municipalities prohibit the deposit of this water into nearby storm water systems. As a result, considerable amount of labor is spent cleaning up the area.

What is needed is an abrasive cutter capable of cutting holes in asphalt that does not require the application of water.

SUMMARY OF THE INVENTION

This and other objects of the invention are met by the asphalt cutter disclosed herein that includes a hollow cylindrical body with a plurality of longitudinally aligned, curved teeth evenly spaced apart along the body's lower perimeter edge. The teeth are curved structures that bend in the forward direction of rotation (e.g. clockwise direction in the Figs.). Each tooth includes a carbide blade with a dual beveled front edge aligned perpendicular to the cylindrical body's axis of rotation. The carbide blade is specifically hardened to withstand the high heat generated when cutting through asphalt. In the preferred embodiment, the teeth are welded into slots formed on to the lower edge of the cylindrical body. In a second embodiment, the teeth are welded directly to a replaceable ring welded onto the lower edge of the cylindrical body. By attaching the teeth to the replaceable ring, the entire set of teeth on the cylindrical body can be easily replaced by merely exchanging the ring.

In the preferred embodiment, each tooth is slightly wider then the sidewall of the cylindrical body and is offset on the sidewall, so that its center axis is positioned slightly outside the outside surface of the cylindrical body to create a circular groove slightly larger in diameter than the cylindrical body. Later, the plug created in the asphalt can be easily removed from the asphalt by inserting a tool into the groove.

In the preferred embodiment, at least one debris slot is formed on the sides of the cylindrical body to help the operator to remove debris trapped inside the cylindrical body.

Normally, the cutter is attached to a heavy piece of equipment that uses an articulating boom arm. Attached to the boom arm is a hydraulic motor. The motor's drive shaft extends downward from the boom arm and is inserted into a hollow neck formed on the top end of the cylindrical body. A bolt and cotter pin are then used to attach the neck to the drive shaft.

An optional elongated pivoting flag guide is provided with the cutter that attaches to the sides of the hydraulic motor's casing The flag guide includes a fixed leg that is securely attached to the side of the motor casing and longitudinally aligned with the motor's drive shaft. Attached to the fixed leg is a pivoting leg that extends upward from the fix leg. The pivoting leg is sufficient in length so that its upper tip may be seen by the operator when operating the machine. When the pivoting leg is longitudinally aligned with the fixed leg, the drive shaft is vertically aligned directly over the desired location on the asphalt. When drilling, the operator controls the boom so that the pivoting legs remain vertically aligned over the fixed legs at all times during the cutting operation. An optional arrow indicator may be printed on the pivoting arm to help the operator visually determine its orientation.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the abrasive cutter attached to a drive shaft of a hydraulic motor mounted on the end of a boom.

FIG. 2 is a top plan view of the cylindrical body.

FIG. 3 is a partial side elevational view of the lower edge of the cylindrical body with a slot formed thereon that receives a tooth.

FIG. 4 is a bottom plan view of the cylindrical body.

FIG. 5 is a sectional side elevational view of the lower section of the cylindrical body showing in greater detail the ring, a tooth with a hardened carbide edge attached thereto, and a cut being made in a layer of asphalt.

FIG. 6 is a side elevational view of a flag guide attached to the sides of the hydraulic motor casing showing how the upper pivoting legs remains vertically aligned at all times as the angle of the motor casing changes.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring to accompanying Figs., there is shown an asphalt cutter, generally indicated by reference number 10 designed to attach to a hydraulic motor 90 attached to the articulating boom 93 on a heavy piece of equipment, such as a backhoe, tractor, or shovel (not shown). Using the cutter 10, one or two workers can easily and quickly cut a plurality of holes in a layer of asphalt 80 in a relatively short time with little or no clean up.

The asphalt cutter 10 that includes a hollow cylindrical body 12 with a plurality of longitudinally aligned teeth 40 evenly spaced apart along the body's lower perimeter edge. The teeth 40 are curved structures that bend in a forward direction of rotation. Formed on each tooth 40 is a hardened carbide blade 50 with a cutting edge 52 perpendicularly aligned with the body's direction of rotation.

More specifically, the cylindrical body 12 is hollow with a lower opening 16 and a top surface 18. Attached to the top surface 18 is a coaxially aligned hollow neck 20. The neck 20 includes a top opening 21. When attaching the cutter 10 to a hydraulic motor 90 attached to the boom 96, the motor's drive shaft 92 is longitudinally aligned and inserted into the neck 20. The neck 20 and drive shaft 92 both include a transversely aligned pair of holes 34 and a bores 36, respectively, in which a bolt 30 may extend. When the drive shaft 92 is extended into the neck 20 and the holes 34 and bores 36 are aligned and registered, the bolt 30 is extended there through and a cotter pin 32 is selectively attached to the distal end of the bolt 30 to securely hold the neck 20 onto the drive shaft 92.

Formed on the side of the cylindrical body 12 is at least one elongated debris slot 24 used to remove debris 82, also called spoils, from the cylindrical body 12 when cutting through a layer of asphalt 80 as shown in FIGS. 1 and 4.

As noted above, a plurality of curved teeth 40 are attached to the lower end of the cylindrical body 12. In the preferred embodiment, the teeth 40 are evenly spaced apart and attached to longitudinally aligned slots 15 formed on the lower edge of the cylindrical body 12. In a second embodiment, the slot 15 and the teeth 40 are evenly spaced apart and attached to the lower edge of a steel ring 38 welded onto the lower edge 14 of the cylindrical body 12 as shown in FIG. 4. In both embodiments, the longitudinal axis of each slot 15 and each tooth 40 is parallel with the longitudinal axis 18 of the cylindrical body 12.

In the preferred embodiment, the teeth 40 are slightly thicker than the adjacent side wall 39 of the cylindrical body 12 or ring 38. Each tooth 40 is also slightly offset from the outside surface of the side wall 39 or ring 38 thereby creating a wide circular groove 78 around the asphalt plug 84 formed in the layer of asphalt 80. If the asphalt plug 84 is not retained in the cylindrical body 12 when it is pulled upward, it can be easily pried upward and removed from the layer of asphalt 80 by inserting the edge of a sharp tool into the groove 78.

As stated above, each tooth 40 is curved in the body's direction of rotation. Welded to the lead edge of each tooth 40 is a carbide blade 50 with a front, dual beveled cutting edge 52 capable of cutting the layer of asphalt 80.

An optional elongated pivoting flag guide 70 is provided that attaches to the sides of the boom 96 or the hydraulic motor casing 90. The flag guide 70 includes a fixed leg 72 that is securely attached to the sides of the motor 92 and longitudinally aligned with the motor's drive shaft 92. Attached to the fixed leg 72 is an upper pivoting leg 74 that extends upward from the fix leg 72. The fixed leg 72 and pivoting leg 74 are sufficient in length so that their upper tips may be seen by the operator when operating the equipment. When the pivoting leg 74 is longitudinally aligned with the fixed leg 72, the operator knows that the drive shaft 92 is vertically aligned directly over the asphalt 80. When drilling, the operator controls the boom 96 so that the drive shaft 92 remains vertically aligned at all times during the cutting operation (see FIG. 6). An optional arrow indicator 75 may be printed on the pivoting leg 74 to help the operator visually determine its orientation.

In the preferred embodiment, the cylindrical body 12 is made of harden steel and measures approximately 8 11/16 inches in diameter and approximately 12 inches in length. The inside bore in the cylindrical body 12 is approximately 8 inches in diameter. The side wall of the cylindrical body 12 is approximately 5/16 inches thick. When slots 15 are formed on the lower edge of the cylindrical body 12, they are approximately ¼ inches in width and ¼ inches in length. In the preferred embodiment, two longitudinally aligned debris slots 24 are formed on the opposite sides of the cylindrical body 12 that measure approximately 6 inches in length and 1½ inches in width.

The neck 20 is approximately 3½ inches in diameter and approximately 5¼ inches in length. The bore 21 formed in the neck 20 is approximately 2⅝ inches in diameter. The transverse holes 34, 36 formed on the neck 20 for the bolt 30 are approximately ¾ inches in diameter. If a ring 38 is used, it is made of harden steel and approximately 8 11/16 inches in diameter and approximately 2 inches in length. The side wall of the ring 38 is approximately 5/16 inches. The teeth 40 extend outward approximately ⅛ inch outside the side wall of the ring 38 the side wall of the or cylindrical body 12. In the preferred embodiment, there are nine teeth 40 evenly spaced apart and attached to the cylindrical body 12 or ring 38. Each tooth 40 measures approximately 1½ inches in length, 1 inch in width, and ⅜ inches in thickness.

In compliance with the statute, the invention described herein has been described in language more or less specific as to structural features. It should be understood however, that the invention is not limited to the specific features shown, since the means and construction shown, is comprised only of the preferred embodiments for putting the invention into effect. The invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the amended claims, appropriately interpreted in accordance with the doctrine of equivalents. 

1. An asphalt cutter used with a piece of equipment with an articulating boom and a drive shaft extending from the end of the boom, said asphalt cutter comprising: a. a hollow cylindrical body with an upper neck and a lower perimeter edge; b. a plurality of longitudinally aligned curved teeth evenly spaced apart and attached to said perimeter edge of said cylindrical body, each said tooth bending in the forward direction of rotation and including a hardened, carbide edge formed thereon, each said tooth also being slightly wider in cross-section than the side wall of said cylindrical body; and, c. means for attaching said cylindrical body to the drive shaft on the articulating boom on the piece of heavy equipment.
 2. The asphalt cutter, as recited in claim 1, wherein said carbide edge has a dual bevel configuration.
 3. The asphalt cutter, as recited in claim 2, wherein each said teeth is located on the outer surface of said cylindrical body.
 4. The asphalt cutter, as recited in claim 1, further including a pivoting flag guide attached to the section of the articulating boom adjacent to said cylindrical body.
 5. The asphalt cutter, as recited in claim 1, each said teeth are welded into a slot formed on said perimeter edge of said cylindrical body.
 6. The asphalt cutter, as recited in claim 1, wherein each said teeth is attached to the outer surface of said cylindrical body.
 7. The asphalt cutter, as recited in claim 2, wherein each said teeth is attached to the outer surface of said cylindrical body.
 8. The asphalt cutter, as recited in claim 1, further including a replaceable ring disposed between the perimeter edge of said cylindrical body and said teeth that enable all of said teeth to be replaced on said cylindrical body by replacing said cylindrical ring.
 9. The asphalt cutter, as recited in claim 2, further including a replaceable ring disposed between the perimeter edge of said cylindrical body.
 10. The asphalt cutter, as recited in claim 1, wherein said cylindrical body means approximately 9 inches in diameter and 12 inches in length.
 11. The asphalt cutter, as recited in claim 1, further including at least one longitudinally aligned debris slot formed on said cylindrical body
 12. The asphalt cutter, as recited in claim 2, further including at least one longitudinally aligned debris slot formed on said cylindrical body
 13. The asphalt cutter, as recited in claim 1, wherein said teeth are wider then the adjacent side walls of said cylindrical body so that a circular groove is formed in the asphalt that is slightly larger that the diameter of said cylindrical body.
 14. The asphalt cutter, as recited in claim 2, wherein said teeth are wider then the adjacent side wall of said cylindrical body so that a circular groove is formed in the asphalt that is slightly larger than same cylindrical body.
 15. The asphalt cutter, as recited in claim 14, further including a pivoting flag guide attached to the section of the articulating boom adjacent to said cylindrical body.
 16. The asphalt cutter, as recited in claim 15, further including at least one longitudinally aligned debris slot formed on said cylindrical body 